Measurement and reporting of received signal strength in NFC-enabled devices

ABSTRACT

An NFC-enabled device including tag emulation circuitry and reader emulation circuitry operates so as to provide a signal strength meter function. The signal strength meter function, in tag emulation mode, measures and reports on how well the tag is coupled to a third party reader field. In reader emulation mode, the signal strength meter function measures and reports how well the reader of the NFC-enabled device couples to a tag that is being read. One exemplary method includes detecting an NFC reader field, operating reader receiver circuitry at the NFC-enabled device so as to at least determine the strength of a signal received from the reader field, generating information representative of the determined strength of the signal received from the reader field at a first time, and performing one or more predetermined actions based at least in part on the one or more signals representative of the determined strength. Predetermined actions may include generating visual, audio, and/or other indications of the received signal strength.

FIELD OF THE INVENTION

The present invention relates generally to Near Field Communication(NFC) devices and the operation and application thereof. Moreparticularly, the present invention relates to methods and apparatus formeasuring and reporting the strength of an NFC reader field.

BACKGROUND

Advances in semiconductor manufacturing technologies have resulted indramatically increased circuit packing densities and higher speeds ofoperation. In turn, these advances have provided designers with theability to produce many processor and communication functions that werenot previously practical. In some instances these functions are combinedin a single highly integrated device. In other instances these functionsare partitioned into two or more devices or chips.

Advances in digital systems architecture, in combination with theadvances in the speed and density of semiconductors, have resulted inthe availability of substantial computing power and digitalcommunications networks for relatively low cost. In turn, this has ledto a vast installed base of computers and other computational platformseach with the ability to communicate with others.

Given the very large installed base of computational platforms, whichincludes at least personal computers and smartphones, it is notsurprising that new operational paradigms for computational devices havebeen developed. It is noted that early computational platforms andcommunication networks served the military/industrial/commercialapplication space, whereas the vast increases in computational andcommunication capacities and concurrent cost reductions have resulted intoday's ubiquitous platforms and networks serving the personalapplication space. Indeed, personal applications have gone beyond thedeskbound model of interacting with a computer to a model whereincomputing and communication hardware are truly personal items, arehighly mobile, and are integrated into the fabric of modern living.Consistent with this usage model for powerful personal computational andcommunication devices, many applications of “on-the-go” computing andcommunication have been, and are being, developed. One class of suchon-the-go applications involves Near Field Communication (NFC) betweendevices. Applications such as conducting financial transactions withstores, banks, trains, busses, and so on may be facilitated by thenear-field coupling of two devices to exchange financial and/or personalinformation.

It will be appreciated that communications involving financial and/orpersonal information should be performed with a high degree ofreliability. High reliability near-field communication is served byoptimally placing the NFC antenna of an NFC reader receiver within thenear-field region of a NFC tag.

What is needed are methods, apparatuses and systems for measuring thereceived signal strength in a near-field communication, and reporting onthe strength of the received signal, or otherwise providing guidance inconnection with improving and maintaining a reliable communicationsconnection.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the invention are described with reference to theaccompanying drawings. In the drawings, like reference numbers indicateidentical or functionally similar elements. Additionally, the left mostdigit(s) of a reference number identifies the drawing in which thereference number first appears.

FIG. 1 is a block diagram illustrating a near field communication (NFC)environment in accordance with the present invention.

FIG. 2 is a high-level block diagram illustrating an NFC-enabled devicehaving both tag and reader functionality, the NFC-enabled devicedisposed adjacent a computational platform having NFC tag readerfunctionality.

FIG. 3 is a high-level block diagram illustrating an NFC-enabled devicehaving both tag and reader functionality, the NFC-enabled devicedisposed adjacent an NFC tag.

FIG. 4 is a flow diagram of a method of in accordance with the presentinvention.

FIG. 5 is a block diagram of an NFC-enabled device having a visualindicator of signal strength.

FIG. 6 is a schematic diagram of a tag emulator antenna shunt regulatorcircuit.

DETAILED DESCRIPTION

Generally, when a pair of NFC-enabled devices, such as a tag and areader, are within a near-field coupling distance of each other, acurrent is induced in the tag's antenna when the reader is active.Alternatively, when another pair of NFC-enabled devices, such as areader and a communicator, are within the near-field coupling distanceof each other, a current change is induced in the reader's antenna whenthe communicator is providing a response to the reader. The reader isthe source of the current and the tag causes the current to change.Typically, a communicator is a NFC-enabled device that may be configuredto operate a reader of a tag and has the capability of switching betweenoperation as the reader or the tag. It should be noted that the readermay be implemented as another communicator. In typical embodiments ofthe present invention, NFC-enabled devices use the induced antennacurrent, which represents the incoming information signal from thereader, to produce a signal that is provided to receiver circuitrywithin the reader to produce in-phase (I) and quadrature (Q) signalsused in processing the incoming information signal. In accordance withthe present invention, the signal strength meter circuitry usesamplitudes of the I and Q signals to provide a measure of the signalstrength received from a reader field, and based at least in part onthis measure of the received signal strength, a report of the strengthof the near-field coupling between the tag and the reader or between thecommunicator and the reader is provided. It is noted that, in both thetag and reader cases, the signal strength is normally derived from acombination of the I and Q signal amplitudes (I²+Q²) to get the vectoramplitude of the signal.

Various methods and apparatus for reporting the received signal strengthresulting from the near-field coupling are disclosed herein.

In alternative embodiments, an NFC-enabled device operating in readeremulation mode uses its reader receiver to determine how well it iscoupling to another NFC-enabled device, such as a tag that is to beread.

The following Detailed Description refers to accompanying drawings toillustrate exemplary embodiments consistent with the invention.References in the Detailed Description to “one exemplary embodiment,”“an illustrative embodiment”, “an exemplary embodiment,” and so on,indicate that the exemplary embodiment described may include aparticular feature, structure, or characteristic, but every exemplaryembodiment may not necessarily include the particular feature,structure, or characteristic. Moreover, such phrases are not necessarilyreferring to the same exemplary embodiment. Further, when a particularfeature, structure, or characteristic is described in connection with anexemplary embodiment, it is within the knowledge of those skilled in therelevant art(s) to affect such feature, structure, or characteristic inconnection with other exemplary embodiments whether or not explicitlydescribed.

The exemplary embodiments described herein are provided for illustrativepurposes, and are not limiting. Other exemplary embodiments arepossible, and modifications may be made to the exemplary embodimentswithin the spirit and scope of the invention. Therefore, the DetailedDescription is not meant to limit the invention. Rather, the scope ofthe invention is defined only in accordance with the following claimsand their equivalents.

The following Detailed Description of the exemplary embodiments will sofully reveal the general nature of the invention that others can, byapplying knowledge of those skilled in relevant art(s), readily modifyand/or adapt for various applications such exemplary embodiments,without undue experimentation, without departing from the spirit andscope of the invention. Therefore, such adaptations and modificationsare intended to be within the meaning and plurality of equivalents ofthe exemplary embodiments based upon the teaching and guidance presentedherein. It is to be understood that the phraseology or terminologyherein is for the purpose of description and not of limitation, suchthat the terminology or phraseology of the present specification is tobe interpreted by those skilled in relevant art(s) in light of theteachings herein.

Although the description of the present invention is to be described interms of NFC, those skilled in the relevant art(s) will recognize thatthe present invention may be applicable to other communications that usethe near field and/or the far field without departing from the spiritand scope of the present invention. For example, although the presentinvention is to be described using NFC capable communication devices,those skilled in the relevant art(s) will recognize that functions ofthese NFC capable communication devices may be applicable to othercommunications devices that use the near field and/or the far fieldwithout departing from the spirit and scope of the present invention.

TERMINOLOGY

As used herein, the expression “Near-field communicator” refers to aproduct that includes at least the resources to provide NFC tag and NFCtag reader functionality. Such products may be sometimes referred to asNFC-enabled devices.

Operating system refers generally to the software that schedules tasks,allocates storage, handles the interface to peripheral hardware andpresents a default interface to the user when no application program isrunning.

As used herein, the term “transponder” refers to circuitry including atransmitter and a receiver such that a transponder may be used totransmit information responsive to receiving a query or other form ofinterrogation signal or communication. It is noted that a transpondermay be implemented without any requirement of integration on a singledie, and the present invention is not limited to any particularpartitioning of transponder functionality amongst any particular numberof components. In typical embodiments, transponders are formed on asingle die.

The terms, chip, die, integrated circuit, semiconductor device, andmicroelectronic device, are of en used interchangeably in the field ofelectronics. The present invention is applicable to all the above asthese terms are generally understood in the field.

With respect to chips, it is common that power, ground, and varioussignals may be coupled between them and other circuit elements viaphysical, electrically conductive connections. Such a point ofconnection may be referred to as an input, output, input/output (I/O),terminal, line, pin, pad, port, interface, or similar variants andcombinations. Although connections between and amongst chips arecommonly made by way of electrical conductors, those skilled in the artwill appreciate that chips and other circuit elements may alternativelybe coupled by way of optical, mechanical, magnetic, electrostatic, andelectromagnetic interfaces.

The term “smartcard” refers to a physical substrate, such as a creditcard sized piece of plastic, having an integrated circuit embeddedtherein. Typically, smartcards are used for financial transactions orsecure access to locked facilities. An active smartcard is one thatincludes an embedded power supply such as a battery. A passive smartcardis one that requires power to be supplied from an external source. Insome instances, the external source is an energization field from whichthe passive smartcard harvests the energy needed to carry out itsdesired function.

An Illustrative Near Field Communications Environment

FIG. 1 is a block diagram showing an NFC environment in accordance withthe present invention. An NFC environment 100 provides wirelesscommunication of information among a first NFC device 102 and a secondNFC device 104 that are sufficiently proximate to each other. Theinformation may include one or more commands to be executed by first NFCdevice 102 and/or second NFC device 104, data from one or more datastorage devices that is to be transferred to first NFC device 102 and/orsecond NFC device 104, or any combination thereof. The data storagedevices may include one or more contactless transponders, one or morecontactless tags, one or more contactless smartcards, any othermachine-readable media that will be apparent to those skilled in therelevant art(s) without departing from the spirit and scope of theinvention, or any combination thereof. Other machine-readable media mayinclude non-transitory storage media, such as but not limited to,volatile memory, e.g., random access memory (RAM); non-volatile memory,e.g., read only memory (ROM), flash memory, magnetic disk storage media,and optical storage media. Still other machine readable media mayinclude electrical, optical, acoustical or other forms of propagatedsignals such as carrier waves, infrared signals, and digital signals, toprovide some examples.

As mentioned above, improvements in manufacturing technologies anddigital architecture have resulted in a number of products and productcategories that were not previously possible or practical to implement.The emerging developments in the area of Near Field Communication (NFC)circuits, systems and applications is making new products and productcategories possible. Products incorporating Near-Field Communicationcapabilities are sometimes referred to as NFC-enabled. For example,mobile phones, smart cards, key fobs, secure access cards, tabletcomputers, or other electronic products that include NFC capabilitiesare referred to as NFC-enabled. Near-field communication allows data tobe communicated from a first NFC-enabled device to a second NFC-enableddevice over short distances. Although a strict definition for the rangeof short distances is not agreed upon in the field, short range for NFCusually is thought of as being less than 4 cm, or within one wavelengthof the selected communication frequency, typically 13.56 MHz.

NFC Device Signal Strength Measurement and Reporting

Typical NFC arrangements involve a pair of devices in which a firstdevice acts as a target or “tag” to respond to a communication and asecond device within a near-field coupling distance of the first deviceacts as a “reader” to initiate the communication. In various embodimentsof the present invention the first device may be equipped with thecircuitry for acting as both a tag and a reader, commonly referred to asa communicator. Electronic products that include NFC tag circuitry alongwith circuitry for other functionality may be referred to as tagemulators, or to have the capability of operating in “tag emulationmode”. Similarly, electronic products that include NFC reader circuitryalong with circuitry for other functionality may be referred to asreader emulators, or to have the capability of operating in “readeremulation mode”.

As will be described in greater detail below, NFC-enabled devices andapplications have utility in at least consumer electronics andindustrial products.

In connection with the following illustrative embodiments, it is notedthat any reference to a computational platform is intended to includesimilar computational devices and computers regardless of their formfactor or input/output configuration. By way of example, and notlimitation, a smartphone is a computational platform.

Methods and apparatus in accordance with the present invention providefor NFC-enabled devices that determine the signal strength received froman NFC reader's field, and to take one or more actions based on thatmeasured signal strength. More particularly, in illustrative embodimentswherein the NFC-enabled device is operating in tag emulation mode,in-phase (I) and quadrature (Q) components of the received signal in thedemodulator of the reader receiver are measured, and one or more outputsare generated, based at least in part on the measured I and Q. These oneor more outputs are typically designed to be user perceivable. Userperceivable outputs can inform a user of the strength of the incomingsignal. In some embodiments, the user perceivable outputs can direct auser regarding how to spatially orient the NFC-enabled device to improvethe received signal strength.

FIG. 2 shows a high-level block diagram of a near-field communicationarrangement 200 that includes a NFC-enabled device 202 having both tag204 and reader 206 functional blocks, the NFC-enabled device 202 beingdisposed adjacent to a second NFC-enable device such as a computationalplatform 210 having NFC tag reader 212 functionality. The circuitryblock that implements NFC Tag 204 includes an NFC antenna 203 and areader receiver 205. NFC-enabled device 202 further includes devicespecific resources 208. In typical embodiments, device specificresources 208 are coupled to both the NFC Tag 204 and the NFC reader206.

Since almost any electronic product may be provided with NFCcapabilities, NFC-enabled devices may include, but are not limited to,computational platforms, smart cards, smart phones, mobile phones,secure access cards, bus and train payment cards, key fobs, utilitymeters, sensors, and so on. Device specific resources 208 may include awide variety of hardware, and may further include software (i.e., storedprogram code). Stored program code, when executed, may implement anoperating system and/or application programs for the NFC-enabled device202. Stored program code is typically stored in memory devices disposedwithin NFC-enabled device 202. Such memory devices may be implementedwith any suitable type of memory circuitry. Those skilled in the artwill recognize that memory may be implemented as addressable regionswithin a single memory chip, or addressable regions of several differentmemory chips. In typical embodiments, at least a portion of the memoryincludes non-volatile memories. Non-volatile memories have thecharacteristic of retaining the contents stored therein even when nopower is applied to those memories. There are a number of types ofnon-volatile memory including, but not limited to, flash memory, ReadOnly Memory (ROM), one-time programmable memory, fuse programmablememory, anti-fuse programmable memory, laser programmable memory,electrically alterable read only memory, and so on. In typicalembodiments, at least a portion of the memory in the NFC-enabled deviceis a non-volatile memory that can be repeatedly written to, as well asread from.

In some embodiments, device specific resources 208 include one or moreprogrammable configuration registers. By way of example, and notlimitation, if NFC-enabled device 202 is a smart phone, then devicespecific resources 208 may include, among other resources, one or morecellular telephone radios, a Bluetooth radio, a GPS radio, a Wi-Firadio, a microprocessor, a graphics processor, volatile and non-volatilememory, stored program code, one or more accelerometers, one or moredigital cameras, a display screen, a display screen controller, audioinputs and outputs, and so on. In typical embodiments NFC Tag 204 andNFC Reader 206 are communicatively coupled to one or more of the devicespecific resources 208.

Still referring to FIG. 2, near-field communication arrangement 200further includes a computational platform 210. Computational platform210 includes computational platform specific resources 211 and an NFCreader 212. It is noted that in various embodiments, NFC tag reader 212may be a reader/writer. An NFC reader/writer is a functional block that,in addition to receiving data from an NFC tag, can also write data tothe tag.

It will be appreciated that NFC-enabled devices in accordance with thepresent invention may be active or passive. Active devices have accessto a power supply such as a battery or other DC power supply (e.g., anAC adaptor). Passive devices are those which need to harvest energy froman external field.

Referring to FIG. 3 an NFC communication arrangement 300 is shown. Inthis arrangement the NFC-enabled device 202 operates in reader emulationmode to read tag 302. In this scenario the present invention is used toprovide an indication of how well NFC reader 208 is coupling to tag 302.

FIG. 4 is a flow diagram of a method 400 in accordance with the presentinvention in which an NFC-enabled device may perform various actionsbased at least in part on the signal strength of a received signal. Inthis illustrative embodiment, when an NFC antenna of the NFC-enableddevice comes within the near-field region of an NFC reader, the readerfield induces a current in the NFC antenna. Illustrative method 400includes detecting 402 the NFC reader field based, at least in part, onthe current in the NFC antenna. In this illustrative embodiment, a fielddetector circuit disposed within the NFC-enabled device is responsiblefor detecting the presence of the reader field and providing one or moresignals to “wake” portions of the NFC-enabled device that are in apower-saving state or a powered-down state. These portions of theNFC-enabled device typically include the ones required to demodulate theincoming signal and process the information obtained therefrom. Method400 continues by operating 404 reader receiver circuitry so as to atleast determine the strength of the signal received from the readerfield. It is noted that the reader receiver circuitry also demodulatesthe incoming signal. As part of that demodulation process, the readerreceiver converts the measured antenna current to digital format andgenerates the I and Q versions of the signal. Since the levels of the Iand Q signals are proportional to the current in the antenna, thesesignals are used as the basis for the signal strength meter function inaccordance with the present invention.

It is noted that the field detector circuit can also give a measure ofthe received signal strength but this is generally a crude, or lowresolution, measurement as compared to the accuracy afforded by usingthe I and Q signal levels. While a more accurate field detector circuitcan be designed, this would require more circuitry, which isdisadvantageous when compared to embodiments of the present inventionthat essentially “re-use” circuitry that already exists in the readerreceiver.

Still referring to FIG. 4, illustrative method 400 continues bygenerating 406 information representative of the determined strength ofthe signal received from the reader field. This information mayrepresent the received signal strength in any convenient format and thepresent invention is not limited by the manner or format in which theinformation is presented to other parts of the NFC-enabled device, to auser, or to other devices or computational platforms. Further, theinformation may be based on the signal strength at a particular time, orthe information may contain data on the signal strength at a series ofpredetermined times, or the information may include one or more averagedor otherwise combined samples of the received signal strength.

Illustrative method 400 further includes performing 408 one or morepredetermined actions based at least in part on the one or more signalsrepresentative of the determined strength. In some embodiments a visualindication of received signal strength is displayed on a touch screendisplay of an NFC-enabled device. Such an indication may be in the formof a bar graph, a dial, a text message, or any other suitable visualindication. In a further aspect, the NFC-enabled device may requestinput from a user with respect to whether to cancel or continue an NFCtransaction based on the received signal strength.

In one illustrative embodiment, an NFC communicator, operating in tagemulation mode, is disposed within the near-field of an NFC tag reader.The present invention is not limited in regard to whether the NFCcommunicator, the NFC tag reader, or both are moved so that thecommunicator is within the near-field of the tag reader. A fielddetector of the communicator detects the presence of the reader'snear-field and wakes up the rest of the communicator. Firmware withinthe communicator is executed by one or more computational resourcesdisposed therein to exercise control over its further operations. Areader receiver circuit within the communicator performs well-knownreceiver functions including, but not limited to, converting from analogto digital, recovering I and Q signals, demodulating the signal from thetag reader and processing the information extracted from the tagreader's signal in accordance with the particular requirements of thiscommunicator. The signal strength meter function of the presentinvention, based on the levels of the I and Q signals provides drivesignals to a visual indicator of received signal strength. In thisillustrative embodiment, the visual indicator is a series of LEDsactivated to form a bar graph indicating the relative strength of thereceived signal. Based on such human perceivable output, a user mayadjust the position or orientation of the communicator to achieve astronger signal.

It is noted that visual output may take any suitable form. In variousembodiments, the visual output of the signal strength meter may take theform of a dial, or numerical digits, or alphabetic characters, orcolored lights, or even an electromechanical meter movement. In stillother embodiments, the human perceivable output is an audio output,where the sound generated is indicative of signal strength.Alternatively, the I and Q signals provides drive signals to a acousticindicator of received signal strength. In this illustrative embodiment,the acoustic represents a sound generating device indicating therelative strength of the received signal. For example, the soundgenerating device may generate a tone or vibrate indicating a lowstrength of the received signal. In still further embodiments, theinformation regarding received signal strength is transmitted via one ormore communication resources of the communicator to another device. Byway of example, and not limitation, the communicator may generate audiodata based on the signal strength information and send that audio datato a Bluetooth earphone paired with the communicator.

FIG. 5 is a simplified block diagram of an illustrative NFC communicator500 in accordance with the present invention. NFC communicator 500includes a housing 501 within which is disposed a printed circuit board502. In this illustrative embodiment, device specific resources 504, tagreader circuitry 506, reader receiver circuitry 508 and signal strengthmeter circuitry are all disposed on printed circuit board 502. Printedcircuit board 502 provides not only a convenient substrate upon which tophysically mount the various components, but also provides a pluralityof conduction paths by which the various circuit blocks and componentscommunicate with each other. It will be appreciated that suchcommunicators may have multiple printed circuit boards each withmultiple components thereon, and that some embodiments will havecomponents on both sides of printed circuit board 502. Similarly, allthe circuitry may be integrated onto a semiconductor substrate to form asingle chip, or there may be a plurality of chips required to implementthe communicator. The present invention is not limited to any particularphysical layout, form factor, or arrangement.

In the illustrative embodiment of FIG. 5, signal strength metercircuitry 510 is coupled to a series a LEDs 512 by means of electricallyconductive interconnect 511. In this way, signal strength metercircuitry 510 can provide the signals that illuminate one or more ofLEDs 512 so as to indicate the strength of the signal received from thereader field.

Signal Strength Versus Error Rate

As noted above, many applications of near-field communication involvetransactions where the tolerance for unreliable data transfer is low.Such applications include, but are not limited to, banking transactions,retail payments, and operating a contactless gate or similar means ofaccessing public transportation.

In a contactless, proximity-based, communication arrangement such asnear-field communication, a small change in the distance between a tagand a tag reader, or in the orientation of their antennas can act toreduce signal strength and in turn the reliability of the communication.

Various embodiments of the present invention alert a user to theoccurrence of low signal strength coupling between an NFC tag and an NFCreader. With the information, the user can intelligently choose tocancel or redo a transaction.

Signal Strength-Stamping

In some embodiments, information received by an NFC-enabled device is“stamped” with one or more signal strength measurements taken in thecourse of receiving the information. That is, one or more signalstrength measurements may be provided to one or more consumers of thereceived information, in one or more formats. The function of providingthis metadata is referred to herein as signal strength-stamping.

It is noted that in some embodiments, the signal strength measurementsare incorporated with the received information, whereas in otherembodiments the signal strength measurements are separated from thereceived information. Signal strength-stamping may be combined withtime-stamping and/or location-stamping.

By stamping received data with one or more signal strength measurements,the NFC-enabled device in accordance with the present invention providesa record that can be used for diagnostic purposes, or to show whetherreceived data was extracted from a signal with sufficient strength toensure reliable data transfer between the near-field coupled NFCdevices.

Averaged DC Current in Tag Emulator Antenna

In an alternative embodiment, when operating in tag emulation mode, thesignal strength from the reader can be determined by measuring theaveraged DC current induced in the tag emulator antenna from the readerwhen the tag shunt regulator is operating. Up to the point where the tagregulator starts to operate, the peak to peak voltage across the coilterminals can be used to represent the field strength. In other words, amethod in accordance with the present invention creates a measurement ofrange by using the peak voltage across the tag emulator antenna whenthis voltage is below the shunt regulator threshold, and uses a measureof the current in the antenna when the tag shunt regulator is shunting.Measuring the current in this way essentially allows the shuntregulator's feedback signal to be “reused”. Such an alternativeembodiment advantageously provides a low-cost tag emulation only NFCdevice (which may still be part of a larger host).

A simplified schematic diagram of an exemplary tag shunt regulatorcircuit is shown FIG. 6. A tag emulator antennal 6502 providesdifferential signal pair 6750.1 and 6750.2, A regulator module 6704adjusts the power level of the differential recovered communicationssignal 6750.1, 6750.2 in response to the regulation control signal 6562.The regulator module 6704 includes a shunt transistor 6708. The shunttransistor 6708 represents a controllable impedance that shunts at leastsome of the recovered communications signal 6750.1 with at least some ofthe differential recovered communications signal 6750.2 when theregulation control signal 6562 is greater than or equal to its thresholdvoltage. The amount of the differential recovered communications signal6750.1, 6750.2 that is shunted together is related to a magnitude of theregulation control signal 6562. The shunt transistor 6708 will shuntmore of the differential recovered communications signal 6750.1, 6750.2together for a larger regulation control signal 6562.

In one embodiment of the present invention, a method of operating anNFC-enabled device, includes detecting, at the NFC-enabled device, anNFC reader field, based at least in part on a current in an antenna ofthe NFC-enabled device; operating reader receiver circuitry at theNFC-enabled device so as to at least determine the strength of a signalreceived from the reader field; generating information representative ofthe determined strength of the signal received from the reader field ata first time; and performing one or more predetermined actions based atleast in part on the one or more signals representative of thedetermined strength.

In some embodiments, performing one or more predetermined actionsincludes generating a user perceivable output representative of thedetermined signal strength. A user perceivable output may include one ormore of a wide variety of visual indicators such as, but not limited toimages, icons, patterns, dials, bar graphs, lights, LEDs, and so on.Outputs may further include audio indicators produced by an NFC-enableddevice with signal strength meter functionality in accordance with thepresent invention. Various embodiments may direct remote devices toproduce signal strength indicators (e.g., Bluetooth earphone paired withthe NFC-enabled device, or similar arrangements).

Some embodiments include waking at least a portion of the NFC-enableddevice from a power-saving or a power-down state, subsequent todetecting the reader field.

Still other embodiments include determining that the received signalstrength is below a threshold value and generating a user perceivableoutput indicative of the received strength being below the thresholdvalue.

Still further embodiments include generating information representativeof the determined strength of the signal received from the reader fieldat each of one or more times subsequent to the first time; and storingthe information associated at least one of the one or more timessubsequent to the first time.

CONCLUSION

It is to be appreciated that the Detailed Description section, and notthe Abstract of the Disclosure, is intended to be used to interpret theclaims. The Abstract of the Disclosure may set forth one or more, butnot all, exemplary embodiments of the invention, and thus, is notintended to limit the invention and the subjoined claims in any way.

The invention has been described above with the aid of functionalbuilding blocks illustrating the implementation of specified functionsand relationships thereof. The boundaries of these functional buildingblocks have been arbitrarily defined herein for the convenience of thedescription. Alternate boundaries may be defined so long as thespecified functions and relationships thereof are appropriatelyperformed.

It will be apparent to those skilled in the relevant art(s) that variouschanges in form and detail can be made therein without departing fromthe spirit and scope of the invention. Thus the invention should not belimited by any of the above-described exemplary embodiments, but shouldbe defined only in accordance with the subjoined claims and theirequivalents.

What is claimed is:
 1. A method of operating an NFC-enabled device,comprising: detecting, by a field detector circuit of the NFC-enableddevice, an NFC reader field based on a current induced within an antennaof the NFC-enabled device; waking, in response to detecting the NFCreader field by the field detector circuit, a powered-down receivercircuit of the NFC-enabled device; generating by the receiver circuit,after waking the powered-down receiver circuit, in-phase (I) andquadrature (Q) components of an incoming signal received from the NFCreader field; determining a strength of the incoming signal receivedfrom the NFC reader field based on the I and Q components generated bythe receiver circuit; generating, at the NFC-enabled device, informationrepresentative of the determined strength at a first time; andgenerating a first user perceivable output representative of thedetermined signal strength, the first user perceivable output configuredto direct a user to spatially orient the NFC-enabled device to improvethe strength of the signal received.
 2. The method of claim 1, whereinthe first user perceivable output comprises a visual display.
 3. Themethod of claim 2, wherein the visual display comprises a bar graph. 4.The method of claim 1, wherein the first user perceivable outputcomprises audio.
 5. The method of claim 1, further comprising:generating a second user perceivable output by transmitting, from theNFC-enabled device, a command to a device physically remote from theNFC-enabled device; wherein the command directs the device physicallyremote from the NFC-enabled device to provide the second userperceivable output representative of the determined signal strength andconfigured to direct the user to spatially orient the NFC-enabled deviceto improve the strength of the signal received.
 6. The method of claim5, wherein the second user perceivable output is selected from the groupconsisting of visual, audio, electrical and mechanical outputs.
 7. Themethod of claim 1, further comprising: determining that the receivedsignal strength is below a threshold value and generating a second userperceivable output indicative of the received strength being below thethreshold value.
 8. The method of claim 1, further comprising:generating information representative of the determined strength of thesignal received from the NFC reader field at a second time subsequent tothe first time; and storing the information associated with the secondtime.
 9. A method of operating an NFC-enabled computational platform,comprising: detecting, by a field detector circuit, a current induced byan NFC reader field in an NFC antenna of the NFC-enabled computationalplatform, wherein the current represents a strength of coupling betweenthe NFC reader field and a tag; powering-up, after detecting by thefield detector circuit the current induced by the NFC reader field, areader receiver circuit; operating the reader receiver circuit, afterpowering-up, to receive a first signal and produce in-phase (I) andquadrature (Q) components of the first signal; generating a secondsignal indicative of the strength of coupling between the NFC readerfield and the tag based on levels of the I and Q components of the firstsignal, at a first time; and producing a first user perceivable outputbased on the second signal indicative of the strength of couplingbetween the NFC reader field and the tag, the first user perceivableoutput configured to direct spatially orienting the NFC-enabledcomputational platform to improve the current induced in the NFC antennaby the NFC reader field.
 10. The method of claim 9, wherein the firstuser perceivable output is a visual output.
 11. The method of claim 9,wherein the first user perceivable output is an audio output.
 12. Themethod of claim 9, further comprising: transmitting a command to adevice physically remote from the NFC-enabled computational platform;wherein the remote device is configured to produce a second userperceivable output.
 13. The method of claim 12, wherein the devicephysically remote from the NFC-enabled device is an earphone.
 14. AnNFC-enabled device, comprising: a plurality of device specific resourcesdisposed within the NFC-enabled device; an NFC tag functional blockcoupled to at least one of the plurality of device specific resources,the NFC tag functional block including a field detector circuitconfigured to detect the presence of a reader field, and a readerreceiver configured to wake from a power-saving state in response to asignal from the field detector circuit; and a signal strength meterfunctional block coupled to the reader receiver; wherein the readerreceiver is further configured to recover in-phase (I) and quadrature(Q) components of signals induced in an NFC antenna, and wherein thesignal strength meter functional block is configured to produce aninformation signal based on levels of the I and Q components, at a firsttime, the information signal configured to direct a user to spatiallyorient the NFC-enabled device to improve a received signal strength. 15.The NFC-enabled device of claim 14, further comprising: an NFC readerfunctional block coupled to at least one of the plurality of devicespecific resources.
 16. The NFC-enabled device of claim 14, furthercomprising: a visual signal strength meter indicator coupled to thesignal strength meter functional block.
 17. The NFC-enabled device ofclaim 14, further comprising: an audio signal strength meter indicatorcoupled to the signal strength meter functional block.
 18. TheNFC-enabled device of claim 14, wherein at least one of the plurality ofdevice specific resources is configured to transmit the informationsignal to a receiver that is physically remote from the NFC-enableddevice.